Process for the treatment of hydrocarbons



Jan. 2l, 1947. J. w. LATCHUM, JR 2,414,551

PROCESS FOR THE TREATMENT OF HYDROCARBONS Filed Nov. so, 1944 2Sheets-Sheet 1 III IIJ 55 Patented Jan. 21, 1947 PROCESS John W.Latchum,

FOR THE TREATMENT F HYDROCARBONS Jr., Bartlesville, Okla., assign` or toPhillips Petroleum Company, a corporation of Delaware ApplicationNovember 30, 1944, Serial No. 565,929

(ci. 26o-666) 9 Claims. l

This invention relates to a process for the treatment of hydrocarbonsand more particularly to a process of treating certain hydrocarbonstreams of the type known in theart as aromatic oils" to recovervaluable components therefrom. Still more particularly it relates to aprocess of treating aromatic oils to recover therefrom separatefractions (1) monocyclic aromatic hydrocarbons especially benzene and/ortoluene, (2) aliphatic conjugated pentadienes, namely, piperylene and/orisoprene and (3) dicyclopentadiene.

Aromatic oils are commonly produced in thermal pyrolysis of the lighterhydrocarbons especially the low-molecular weight paraillns, althoughthey are also obtained in the production of manufactured gas. In somecases aromatic oils are present in naturally occurring oils or areproduced as 'by-products in various refinery operations. For the mostpart, however, they are produced by high-temperature operations. See

^ for example, Chapter 5 of Ellis, Chemistry of Petroleum Derivatives,volumes 1 and 2, entitled Production of aromatic hydrocarbonsbypyrolysis of petroleum hydrocarbons." Cracking processes in particularyield mixtures containing benzene, toluene, piperylene, isoprene andcyclopentadiene; see Ellis, loc. cit. vol. 2, page 144.

Petroleum hydrocarbon conversion processes, especially those involvingcracking or high temperature Dyrolysis yield aromatic oils of the typeemployed as raw material in the present invention'. For example, thepyrolysls of ethane and/or propane at atmospheric pressure at atemperature of from 1450 to 1600 degrees F. for a period of time of from2 to 0.1 seconds, yields a' mixture containing butadiene, isoprene,piperylene, cyclopentadiene, and monocyclic aromatics such as benzeneand toluene. See U. S. Patents to F. E. Frey, Nos. 2,376,425 and2,376,426.

Aromatic oils to which the present invention may be applied are obtainedas by-products in the pyrolytic treatment of propane to produceethylene. For example, the copending application of Carl J. Maki, Ser.No. 510,172, led November 13, 1943, discloses this method of producingethylene. The gaseous eiluent from the cracking of propane at 1400 F.and 6 to 8 pounds pressure in accordance with said application is cooledand compressed to drop out heavy hydrocarbons which contain aromaticoils. Upon depropanizing or debutanzing the resulting gaseous streamthere is obtained a kettle product which is an aromatic oil. Any ofthese aromatic oils may be used as feed in the practice of the presentinvention. The kettle product referred to is preferably treated in themanner disclosed in the c opending application of K H. Hachmuth, Ser.No. 454,312, filed August 10, 1942, for the vremoval of C4 hydrocarbonsincluding butadiene whereupon `feed to the present invention.

Aromatic oils are also produced as luy-products in processes for theproduction of aliphatic con- Jugated dioleilns from the correspondingoleflns `or paraflins, especially butadiene from normal butene or normalbutane. For example, in the two-stage dehydrogenation of normal butaneto butadienein accordance with the process described in U. S. patent toK. H. Hachmuch, No. 2,386,310, aromatic oils are produced in thecompression systemsoperating on the efliuents from the first and secondstages. Another fraction of aromatic oils is obtained in the final orbutene-Z column in which butene-2j recycle is separated overhead from akettle fraction of aromatic oils. The copending application of K. H.Hachmuth, Ser. No. 534,599, filed May 8, 1944, discloses an improvedmethod of removing the butene--2 from this aromatic oil kettle fractionwhereby polymerization thereof is prevented.

It appears that those pyrolytic or thermal hydrocarbon conversionprocesses which yield one member of the group consisting of monocyclicaromatics (such as benzene), cyclopentadiene, and aliphatic conjugatedpentadienes also yield appreciable quantities of-the other members ofthis group as accompanying products. See, in addition to chapter 5 ofEllis, above cited, chapter 4 on production of unsaturated hydrocarbonsespecially the section on diolefins, chapter 3 on cracking processes andtheir products and chapter 2 on thermal decompositionof hydrocarbons. Asurvey of sources of cyclopentadiene and accompanying hydrocarbons will'be found in the article of Wilson and Wells, entitled The chemistry andutilization of cyclopentadiene," appearing in Chemical Reviews, `vol.34, February, 1944, pages 1 to 50, especially pages 2 to 4. It isevident that the formation of any one of these three classes ofhydrocarbons by high temperature hydrocarbon conversion processes andthe like is closely linked up with the formationof the others in amanner but imperfectly understood at present. For these reasons,aro-matic oils containing these three types of material recovered by myprocess are quite commonly available, so that ample supplies of feed forthefprocess of the present invention are assured. As a matter of factaromatic oils are often considered to be objectionable by-products ofprocesses making other materials such as dehydrogenation, cracking,pyrolysis, etc., and have often been discarded as of little or no value.Disposal of these aromatic oil streams has been a source of expense. Myinvention not only eliminates the problem of disposal but provides asimple and commercially feasible method of recovering highly valuableorganic chemicals.

The principal object of the present invention is to provide animprovedmethod of recovering L valuable components of aromatic oils.

Another object is to provide a commercially feasible method ofrecovering separate fractions l of monocyclic aromatic hydrocarbons,cyclopentadimer, dicyclopentadiene, from an aromatic oil containingcyclopentadiene in the form of the monomer or the dimeror both. Anotherobject is'to provide such a process wherein there is simultaneouslyrecovered a monocyclic aromatic fraction and an aliphatic pentadienefraction. Another object is to provide a process of the foregoing typewhich is simple and economical, requires a minimum of relatively simpleequipment, and is easy to operate. Numerousother objects willhereinafter appear or become apparent to those skilled in the art fromthe following illustrative description of the best mode known-to me ofcarrying out my invention.

In the accompanying drawings: Fig. 1 portrays diagrammatically onearrangement of equipment which has been found very satisfactory incarrying out the present invention. Fig. 2 is a graphical presentationof the initial concentration of cyclopentadiene vs. final concentrationof dimer showing influence of time. temperature and initialconcentration of monomer upon nal concentration of dimer.

My invention is a method of recovering cyclopentadiene in the form ofdicyclopentadlene from an aromatic oil mixture containingcyclopentadiene in the form of the monomer (as will hereinafter appear,if the feed contains cyclopentadiene in the form of the dimer the feedis rst treated to convert most or substantially all of the dimer tomonomer) in admixturewith aromatic hydrocarbon and aliphatic conjugatedpentadiene which comprises fractionally distilling said mixture undersuch conditions that substantially all of said cyclopentadiene monomerand aliphatic conjugated pentadiene are taken overhead whilesubstantially all of said aromatic hydrocarbon is taken olf in thekettle product, subjecting said overhead to an elevated temperature fora period of time such as to dimerize a major proportion, and preferablysubstantially all, of the cyclopentadiene without substantiallypolymerizing the other unsaturated hydrocarbon content thereof, andfractionally distilling the resulting mixture under such conditions thatsubstantially all of the dicyclopentadiene content thereof is taken voffin the kettle product. Preferably the condii tions in the latterdistillation are such that substantially no dedimerization ofdicyclopentadiene in the column takes place. y

Referring now to Fig. 1 of the accompanying drawings:

In accordance with the present invention the aromatic oil containingcyclopentadiene in the form of monomer or dimer or both, aromatichydrocarbons such as benzene and toluene, and aliphatic conjugatedpentadiene such as piperylene and isoprene is employed as the feedentering via line I. If dicyclopentadiene is present, the feed unit 2 toan elevated temperature for a period of `time such that all of thedicyclopentadiene in the mixture is converted to the monomer. lForexample, it may be heated to 350 F. for 6 hours.

'The depolymerization step is preferably conducted with the feed in thevapor phase.- Vapor phase 4 depolymerization results in conversion ofany polymers heavier than the dimer present in the vfeed to the monomeralso. The depolymerization effluent is condensed in condenser 3A to formthe fractionator feed. Other methods of converting the dimer to themonomer will be obvious to those skilled in the art. Thedepolymerization step is omitted where the feed contains no dimer.

The resulting dimer-free feed flowing via line 3 or. where all of thecyclopentadiene content of the original feed is in the form of monomer.the original feed flowing via line 4, passes via line 5 intofractionating column 6 where it is fractionally distilled under suchconditions that all of the cyclopentadiene, piperylene, isoprene and anylighter material pass overhead while all of the benezene, toluene andany heavier material are withdrawn as kettle product. It has been foundpreferable to maintain bottom time and temperature conditions such thatsubstantially no dimer leaves in the bottom product and to employ steamstripping in combination with the continuous fractional distillation.Raw steam is injected via line 1 directly into the bottom of the column6 to aid in the fractionation. A Water layer is withdrawn from the upperportion of the column via line 8, for example, by means of atrapout trayof known type (not shown), and is cooled and pumped into the top of thecolumn via line 9 as the sole reflux. By the use of steam stripping asharp separation is obtained, all of the piperylene and lighter goingoverhead via line I0 and the heavier-than-piperylene material going outthe base of the column via line 8A, this being the benzene and tolueneconcentrate. While use of the dephlegmator with a Water reux in themanner described above and shown in the drawings is most highlypreferred, it may in some cases be dispensed with, column 6 being reuxedin the conventional manner; however, operation in such manner involvesthe sacrifice of the many advantages accruing from the refluxing withwater. In some instances column Ii may be refluxed with the water layerobtained upon condensation of the overhead.

The overheadproduct is cooled in unit II and passed to accumulator I2from which a water layer may separate and be drawn off vialine I3. Theemulsion of water and hydrocarbons obtained by condensing the overheadfrom column 6 is often very slow-breaking so that if sole reliance isplaced upon gravity to effect the separation of water in vessel I2,several hours must elapse. However, failure to separate the water is notparticularly harmful in the later steps of the process the principaldisadvantage being the added load on subsequent units of the equipment.

The overhead product is next passed to dimerizing unit I4 in which it isreheated to convert the monomeric cyclopentadiene to the dimer undersuitable conditions of time and temperature known to the art. Theconversion may be carried out by heating for the proper period of ,timewhereupon the mixture may be quenched in any suitable manner. 'I'hisconversion may be vaccomplished without significantly polymerizing theother unsaturated hydrocarbons in the mixture.

The dimerized product is cooled and fed via line I5 to fractionationcolumn IB where it is fractionated at relatively low temperatures withthe bottom temperature being preferably not over 212 F. so that littleif any of the dimer will be converted to monomer. In column I6 thepiperylene and lighter go overhead and are removed via line I8 while thedimer is taken of! as kettle product via boiling between piperylene andline I 9. Care must be taken to keep the temperature above 94 F. untilit is in the shipping container so as to prevent formation of the solidphase. During the fractionation steam or other inert gas is injected asa stripping medium into the bottom of column I6.

The piperylene and lighter fraction withdrawn via line I8 may be treatedin any manner as by refractionation to secure a piperylene kettleproduct, the overhead being discarded or refractionated to yieldisoprene. The benzene-toluene concentrate withdrawn via line 8 isrefractionated to give raw toluene and raw benzene and the residue isdiscarded. The raw products are purified to the grade desired by meanswell-known to the art.

Operating conditions for column 6 may be as follows: pressure rangingfrom atmospheric to 10 pounds gauge, conveniently 5 pounds; bottomtemperature 150 to 170 F., conveniently 160 F. at 5 lbs. gauge; toptemperature 100 to 120 F., conveniently 115 F. at 5 lbs. gauge.

Operating conditions for column I6 may be as follows: pressure rangingfrom atmospheric to 10 pounds gauge, conveniently 5 pounds; bottomtemperature ranging from 170 to 212 F., conveniently 212 F. at 5 lbs.gauge; top temperature of 120 to 130 F., conveniently 125 F. at 5 lbs.gauge. Fractionator I6 functions somewhat like a. stripper since itsprincipal function is that of i' removing piperylene and lighter fromthe dimer of cyclopentadiene. It is preferred that the bottoms productin column I6 not be reboile'd in order to avoid dedimerization. Thestripping action of the steam or other inert gas introduced via line I'Iaids markedly in the separation in column I 6 and in keeping the bottomtemperature in column I 6 at a suitable low level so that dedimerization of dicyclopentadiene is prevented.

In some cases it may be found desirable to introduce into the feedentering column I6, or at some other point in column I6, a paraiiinhydrocarbon having` a boiling point below dicyclopentadiene (338 F.) andpreferably at least 100 degrees F. therebelow, such as certain octanes,heptanes, hexanes, etc. The parains are em,- ployed because of theirinertness. Such a paraffin should preferably boil substantially abovepiperylene (109112 F.), i. e., be a hexane or heavier in which case itappears in the bottom product, keeping the bottom temperature down,allowing reboiling of the bottom product at a ternperature well belowthe point at which dedimerization of dicyclopentadieneoccurs.

Such a parailin, dicyclopentadiene, has the further advantage that it isa solvent or suspension medium for dicyclopentadiene, preventingsolidification thereof or tendency to solidify. Such a paraffin may beintroduced via line I'I. If desired such a paraiiin may be introduced inthe original feed in line I in which case it must in practice be hexanein order to insure its going overhead in column 6 and its presence incolumn I6 tadiene and above piperylene.

If desired there may be present in the feed to column I6 or there may beemployed as the stripping agent fed in via line I1 a parafn boilingbelow piperylene such as a pentane, a butane, propane, ethane, etc. Sucha lower paraffin appears in the overhead of column I6 and aids greatlyin the stripping of the dicyclopentadiene in column I6 and in themaintenance of a low temperature in this column. It is desirable thatthe fractionation and stripping in the column Hexanes are preferredbecause they boil well below dicyclopentake place very rapidly in orderto avoid a. long residence time of the dicyclopentadiene in col'- umn I6.

The pressure on the system at any point depends on the temperature.Preferably the`column B and I6 are run at slightly above atmosphericpressure. Depolymerization unit 2 is operated at substantially similarpressures in order to avoid the necessity for high pressure pumps orreducers or for high pressure differentials, namely, the pressure of thefeed, e. g., in dedimerizing unit 2, will be somewhat above that incolumn 0 in order to force the material through the column.

Conditions for operation of dimerizer I4 may be determined readily bythose skilled in the art. Fig. 2 portrays graphically the inter-relationbetween initial concentration of cyclopentadiene, final concentration ofdimer thereof, and time at one temperature, namely 300 F. Similar graphsmay be plotted for any temperature level such as 200, and 250 F. To usethe chart. the initial concentration of monomer is fixed. Then, 'knowingeither final concentration oi' dimer or time, the other mined. Theslanting lines represent the percentage of dimer in the treated product.

Dimerizer I 4 is preferably operated under 1iq uid phase conditions. Thematerial in dimerizer I4 is ordinarily maintained under sufflcientlyelevated pressure to maintain it in liquid phase. 'I'he pressure willdepend upon its composition and upon the dimerizing temperature used. Ingeneral it will be of the order of several hundred pounds per squareinch gauge. For example, at 300 F. it may be about 400 pounds per squareinch gauge. Vapor phase operation may be used but is less desirable.

The conditions of depolymerizationin unit 2 may readily be determinedfor any given feed by those skilled in the art in the light ofpresent-day knowledge of the dedimerization of dicyclopentadiene. Thisreaction is preferably carried out in vapor phase.

.Following are specific examples of the practice of my invention.

ExAmLr: I

A feed stream having the following composition was fed to a unitessentially as shown in the drawings via line I. The feed was a lowstage accumulator or scrubber oil obtained as a by-product in thecracking of ethane and propane to Analysis of feed-line 1 LiquidComponent vulume Pcntadiene 2-methylbutene-l Isoprene. Pentene-2.-

Residue...

This feed was passed via lines l and to fractionating column B'at therate of 2000 gallons per 24-hour day. Column 6 was of the eonven tionaltype having thirty (30) bubble trays and was provided with the usualsteam reboiler, and with a, water separating tray in the upper section.Steam was fed into the bottom of column 6 by means of line i at the rateof 300 pounds per day. Column 6 was operated at a pressure of 5 poundsper square inch gauge and with a kettle temperature of 160 F. and a toptemperature of 115 F. The kettle product withdrawn via line 8 had thefollowing analysis:

Analysiskettle product-line 8A The overhead vapors in line I0 werecondensed in cooler ll and accumulated in vessel i2. The condensate hadthe following analysis on a waterfree basis:

Exner.: 1I

Afeed having the following analysis was fed into the system via line I:

This material was the aromatic oil obtained as a heavy product in therecovery of butadiene from the gaseous eiiiuent from the compressionsystem applied to the cracking eiliuent from which, the feed of ExampleI was derived.

The feed was passed through dedimerizing unit 2 Where it was heated at21.3 pounds gauge to 425.F. for 15 minutes which effected dedimerizationof substantially all the dimer of cyclopentadiene. The resulting streamwas passed by lines 3 and 5 at the rate of 2000 gallons per 24- hour dayinto column 6 operated as in Example I. The kettle product of column 6had the following analysis:

Analysis-overhead productline 10 so Kettle product-.line 8 Liquid LiquidComponent volume Component volume per cent per cent Pentadiene- 31-0s 3559. 2-methylbutene-l 9- 23 Unsaturates in benzene 9. Isoprene. 4 27Intermediate to dicyclopentadiene 21. Pentene 4* 60 Residue..- 0.2-methyibutene-2 4. 52 Cyclopentadiene 24. Piperylen 22.00 o Theoverhead product of column analyzed as The overhead condensate was thenfed into dimerizer I4 where it was heated to a temperature of 300 F. for30 minutes under pressure sufficient to maintain liquid phase therebyconverting 96 per cent of monomeric cyclopentadiene to the dimer. Theresulting mixture was then passed via line i5 to column I6 which wasoperated at a pressure of 5 pounds per square inch gauge and with abottom temperature of 212 F. and a top temperature of 125 F. Steam wasfed in via line i1 at the rate of 200 pounds per day. The kettle producthad the following analysis:

Analysis-kettle productline 19 follows on a water-free basis:

Overhead product-line 10 Liquid volume per cent Component Cr-Clgyciopentadiene 57 Liquid operated a-s in Example I. The overheadproduct component volumet had the following analysis:

T0911 De Overhead product-line 18 r(.liycloplentadiene (as dimer) 903gLi id ene u .pery 60 Component voaime percent The overhead product fromcolumn I6 had C the following analysis on a water-free basis: Csenmienn9%?. Analysis-overhead product-line 18 65 Bamm" f 65 Li um The kettleproduct of column 16 analyzed as Component voime follows per mnt Kettleproduct-linen? Pentadiem 39.50 Li 'Ia-methylbutene-l 7o Component voixgiS0 rene. Pesten-2 5 93 per cent 2-methylbutene-2 5. B3 C plage-Miami1.00 :n IR 0.5 Piperylene 30. 34 Dicyclopentadlene 99. 5

From the foregoing it will be seen that the present invention provides ahighly improved method of recovering aromatics, aliphatic conjugatedpentadiene, and cyclopentadiene from aromatic oil containing the same.The process of the present invention presents numerous advantages amongwhich are the small equipment requirements, the simplicity of theoperation and its ease of control, the effectiveness of the recovery ofthree valuable hydrocarbons from materials which have heretofore beenwasted, and the fact that the cyclopentadiene is recovered as the dimerwhich is convenient for shipping and 10 the cyclopentadiene andaliphatic conjugated pentadiene are taken overhead and substantially allof said monocyclic aromatic hydrocarbon is taken ofi in the kettleproduct, injecting liquid water into the top of said column as the solereflux, withdrawing a water layer from a lower handling since it is anon-volatile liquid or solid at ambient temperatures. Another advantageis that the three product streams are very little contaminated withmaterial belonging in other streams, so that purification of the productstreams is much simplified. Another advantage is that dicyclopentadieneof excellent purity is obtained as a product. Another` advantage is thatthe injection of steam into the columns in which the 'fractionaldistillations are conducted suppresses polymerization of unsaturatesincluding cyclopentadiene and aliphatic conjugated pentadiene. Numerousother advantages will be apparent to those skilled in the art.

I claim:

1 The-process of recovering cyclopentadiene in the form ofdicyclopentadiene from an aromatic oil mixture containingdicyclopentadiene in admixture with monccyclic aromatic hydrocarbon andaliphatic conjugated pentadiene which comprises heating said mixture toan elevatedtemperature and for a period of time such that substantiallyall of said dicyclopentadiene is converted to the monomer, passing theresulting substantially dicyclopentadiene-free mixture to afractionation column and there distilling same under such condition thatsubstantially all of the cyclopentadiene and aliphatic conjugatedpentadiene are taken overhead and substantially all of said monocyclicaromatic hydrocarbon is taken oif in the kettle product, injectingsteamdirectly into the bottom of said column, withdrawing a water layerfrom said column at a point near but above the feed entry to saidcolumn, cooling the water layer so withdrawn and injecting it into thetop of said column as the sole reflux, condensing said overhead,subjecting the resulting condensate to an elevated temperature for aperiod of time suchas to dimerize substantially all of thecyclopentadiene Without substantially polymerizing the other unsaturatedhydrocarbon content thereof, passing the resulting mixture to a secondfractionation column and there distilling same under such conditionsthat substantially all of the aliphatic conjugated pentadiene 'contentthereof and lighter are taken overhead While sub- ,santially all of thedicyclopentadiene content thereof is taken olf in substantially pureform as the kettle product and that substantially no Vcledimerization ofdicyclopentadiene takes place.

2. The process of recovering cyclopentadiene in the formofdicyclopentadiene from an aromatic oil mixture containingdicyclopentadienein admixture with monocyclic aromatic hydrocarbon andaliphatic conjugated pentadiene Which comprises heating said mixture ltoan elevated .temperature and for a period of time such thatsubstantially all of said dicyclopentadiene is converted to the monomer,passing the resulting substantially dicyclopentadiene-free.mixture to afractionation coltimn and there distilling same under such conditionsthat substantially all of point in said column, said lower point beingnear but above the point of feed entry to said column, condensing saidoverhead, subjecting the resulting condensate to an elevated temperaturefor a period of time such as to dimerize substantially all of thecyclopentadiene without substantially polymerizing the other unsaturatedhydrocarbon content thereof, passing the resulting mixture to a secondfractionation column and there distilling same under such conditionsthat substantially all of the aliphatic conjugated pentadiene contentthereof and lighter are taken overhead while substantially all of thedicyclopentadiene content thereof is taken off in substantially pureform as the kettle product and that substantially no dedimerization ofdicyclopentadiene takes place.

The process of claim 1 wherein said dedimerization is carried out withthe aromatic oil mixture in the vapor phase.

4. The process of claim 1 wherein said firstnamed column is operated ata. pressure ranging from atmospheric to 10 pounds gauge, with abottom"temperature ranging from 150 to 170 F. and a top temperatureranging from to 120 F., and said second column is operated at a pressureranging from atmospheric to 10 pounds gauge, with a bottom temperatureranging from 170 to 212 F. and a top temperature ranging from 120 to 130F.

5. The process of claim 1 wherein said first; named column is operatedat a pressure of approximately 5 pounds gauge, with a bottom temperatureof approximately 160 F. and a top temperature of approximately v F. andsaid second column is operated at a pressure of approximately 5 poundsgauge, with a bottom temperature of approximately 212 F. and a toptemperature of approximately 125 F.

f ated Without reboiling of its bottoms product, and

an inert gaseous stripping medium is injected directly into the bottomof said second column.

7. The process of claim 1 wherein said firstnamedcolumn is operated at apressure ranging from atmospheric to 10 pounds gauge, with a bottomtemperature ranging from 150 to 170 F. and a top temperature rangingfrom 100 to F., said second column is operated at a pressure rangingfrom atmospheric to 10 pounds gauge, with a bottom temperature rangingfrom 170 to 212 F. and a top temperature ranging from 120 to 130 F.,said second column is operated without reboiling of its bottoms product,and steamas a stripping medium is injected directly into the bottom ofsaid second column.

8. The process of claim 1 wherein said firstnamed column is operated ata pressure ranging from atmospheric to 10 pounds gauge, with a bottomtemperature ranging from to 170 F. and a top temperature ranging from100 to 120 F.,

said second column is operated at a.. pressure low piperylene as astripping medium is injected ranging from atmospheric to 10 poundsgauge, directly into the bottom of said second column.4

with a, bottom temperature ranging from 170 to 9. The process of claim 1wherein hexane is 212 F. and a. top temperature ranging from 120 presentin substantial amount in said second to 130 F.. said second column isoperated with- 6 column and appears in the kettle product in ad outreboiling of its bottoms product, and a. mixture with saiddicyciopentadiene.

parafn hydrocarbon having a boiling point be- JOHN W. LATCHUM, JR.

